[PATCH 6.18 267/333] xfs: fix integer overflow in bmap intent sort comparator

Greg Kroah-Hartman
2026-03-17T17:24:08Z

From: Long Li <leo.lilong@huawei.com>

commit 362c490980867930a098b99f421268fbd7ca05fd upstream.

xfs_bmap_update_diff_items() sorts bmap intents by inode number using
a subtraction of two xfs_ino_t (uint64_t) values, with the result
truncated to int. This is incorrect when two inode numbers differ by
more than INT_MAX (2^31 - 1), which is entirely possible on large XFS
filesystems.

Fix this by replacing the subtraction with cmp_int().

Cc: <stable@vger.kernel.org> # v4.9
Fixes: 9f3afb57d5f1 ("xfs: implement deferred bmbt map/unmap operations")
Signed-off-by: Long Li <leo.lilong@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/xfs/xfs_bmap_item.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -247,7 +247,7 @@ xfs_bmap_update_diff_items(
struct xfs_bmap_intent *ba = bi_entry(a);
struct xfs_bmap_intent *bb = bi_entry(b);

- return ba->bi_owner->i_ino - bb->bi_owner->i_ino;
+ return cmp_int(ba->bi_owner->i_ino, bb->bi_owner->i_ino);
}

/* Log bmap updates in the intent item. */